1. Field of the Invention
This invention relates to a self-propelled vehicle with a loader, and more particularly to a vehicle such as a tractor with a working implement such as a front loader attached thereto.
2. Description of the Related Art
Conventionally, as an example of self-propelled vehicle with a loader, a tractor has a front loader attached the front thereof. This front loader tractor has support bases laterally outwardly of the front of a tractor body, and main frames erected on the support bases. Each main frame has right and left side walls and a rear wall, and opens forward and upward. A side frame is inserted and attached between the right and left side walls of each main frame. When attaching the side frame, an engaging element disposed in a lower position of the side frame is fitted, while turning downward about a transverse axis, on an engageable element disposed in the main frame, and thereafter a connecting pin is removably extended through the main frame and side frame above the engaging and engageable elements. The side frame has a proximal end of a boom pivotally attached to an upper position thereof, the boom having a bucket at a distal end thereof. A boom cylinder extends between the boom and side frame for swinging the boom.
Such a vehicle with a loader, generally, includes braces disposed laterally of the front of the tractor. Each brace extends forward and downward from the main frame (or side frame), and has a forward end connected to the tractor body. This construction is intended to distribute a load applied from the boom to the side frame and main frame. Such a loader is called a braced loader.
However, where the braced loader is used, the braces disposed laterally of a hood of the tractor are obstructive to a maintenance operation for the interior of the hood, for example. The braces are obstructive also to the driver""s forward view. Further, the braces are undesirable from the point of view of outward appearance. Thus, it is desired to attach a braceless loader to the tractor. However, when a load is applied from the boom to the side frame and main frame, in the absence of braces, stress concentrates on a lower portion of the main frame or the lower end thereof fixed to the support base. This gives rise to a problem of strength.
This invention has been made having regard to the state of the art noted above, and its object is to provide a technique for solving the problem of strength with a self-propelled vehicle with a braceless loader attached thereto.
The above object is fulfiled, according to this invention by a self-propelled vehicle with a loader, comprising a vehicle body extending in a fore and aft direction of the vehicle; support bases extending laterally outwardly from opposite sides of the vehicle body; main frames erected on the support bases, respectively, each of the main frames being in form of a box opening forward and upward and including right and left side walls and a rear wall, the box containing an engageable element;
side frames each mounted in the box, each of the side frames having an engaging element disposed in a lower region thereof for rotatably fitting from above on the engageable element; booms pivotably connected to upper end regions of the side frames, respectively; boom cylinders for swinging the booms relative to the side frames, respectively; and reinforcing members each disposed between the right and left side walls of one of the main frames, each of the reinforcing members having a front reinforcing portion extending upward from one of the support bases, a rear reinforcing portion disposed rearwardly of a lower portion of one of the side frames and extending above the engageable element, and an intermediate reinforcing portion interconnecting an upper end of the front reinforcing portions and a lower end of the rear reinforcing portion.
With the reinforcing members having the above construction, the main frames can reliably receive and bear a load transmitted from the side frames, which load is applied to the engageable elements in time of loader operation. Thus, the main frames can sufficiently withstand the load occurring in time of loader operation, with a high degree of reliability, though braces are dispensed with.
In order to distribute the load applied to the main frames efficiently to the side frames, this invention provides reinforcing units each extending from a region the engageable element of one of the main frames to one of the subframes. In order to secure sufficient strength against a torsional force occurring between the main frames and subframes, each reinforcing unit in a preferred embodiment of this invention defines a box-like section with one of the support bases.
Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings.